My car has died three times, the third was the charm and haven't been able to get it going since. The first two times it died; the first was in a touch free car wash and it just died, no sputtering or anything, the second was about ten minutes after a touch free car wash, I was driving and it started sputtering/no power/couldn't raise rpms, then died. The last time, it had been raining all day, I was driving late at night and the symptoms were similar to the second time when it died. The first two times I was able to "fix" (or so I thought) by unplugging plug wires and drying them out. Car started after taking a paper towel and wiping distributor cap and wires. The third time this didn't work. Towed car home and have changed rpm sensor and distributor cap. Fuel pump relay works/car is getting fuel to the injectors. It seems as though whatever tells the injectors to inject, isn't working. Going to swap out the brain to see if that works. Will a non-turbo brain work in a turbo, just to get it started? I have a turbo brain, but wanted to know if non-turbo would work anyways. Anyone have any suggestions or questions to further diagnos? Any help would be much appreciated.

Go to www.stepbystepvolvo.com for free how-to guide on 740/940 no-starts.

The more opinions the better. Here are some more. Do you still have spark after all the trials?. If you do, I say is still fuel related or (I don't konow if Turbos have EGR, but) a open EGR will cause the car to stall at idle and no start. A dead idle valve will do about the same. If you don't have spark and have a new rpm sensor the coil or power stage, may be cause.

I vote for the radio suppression relay being at fault. It is located here:


To check that guess simply remove the relay and use a piece of wire to jumper the two sockets that correspond to the two heaviest wires on the connector. Use a piece of insulated wire stripped on both ends or be careful not to let a bare piece short to ground.

If the car starts with the jumper in place you can usually open up the relay box and resolder the circuit board. When you are done reseal the relay cover with RTV. Good luck.

Randy

Dear Mr. Young,

May this find you well. The fuel injection relay - formally (but misleadingly) known as the radio interference suppression relay - controls delivery of power to the fuel injectors. It is located on the inner fender wall. On turbo-equipped cars, I believe it is on the driver's side (North American models), just to the rear of the headlight. On normally-aspirated cars, it is on the passenger side of the car, just behind the headlight.

You should carry a spare in the glove box. Apart from dextrous fingers, no tools are needed to change this relay.

You might also want to check the crank (RPM) sensor. The wiring harness gets brittle, cracks, and allows the wires to touch, or water to get to the wires. Loss of this sensor's signal causes the fuel pump to shut-down.

As you have fuel pressure, the RPM sensor may be OK. However, the intermittent nature of the failures - and the failure after a car wash - suggests that this sensor may be "on the way out".

To see if the RPM sensor might also be at fault, wiggle the harness - it is about 1/4" (6.5 mm) in diameter, and drops down towards the transmission bell housing, on the firewall, on passenger side of the engine. If wiggling the wire causes the engine to stop running, you should replace this sensor.

Hope this helps. Please post your findings.

Yours faithfully,

Spook

Just took the radio suppression relay off of my 740 turbo and put it on my 940...didn't work. To make sure they are compatible, I took the one from the 940 and put it in the 740; ran fine. So this isn't the problem, unless the 940's is compatible with the 740 but the 740's isn't compatible with the 940. I'm sure this isn't the case. So now I've put a new rpm sensor on, new distributor cap, and swapped the radio suppression relay with a known working one and the car still won't run. Is the next step changing out the brain? Is there anything else I should check before going to the brain? It's a process of elimination now...what's next? Thanks for the replies so far.

No-Start Analysis

1) During starter cranking, the Crank Position Sensor sends timing pulses to Ignition Control Unit (ICU)

2-a) The ICU propagates these timing pulses to the Power Stage (aka Ignition Amplifier) to initiate spark at the coil.

2-b) The ICU also propagates these pulses to the FI ECU, to allow FI operation
(no ICU pulses means no FI operation).

3) The FI ECU energizes the Fuel Relay, which has two outputs (see below).

3-a) Fuel relay sends power to fuel pumps, and

3-b) also powers AMM, IAC, ECU, and Injectors (via Radio Suppression Relay)

When all these events are successful, the engine runs until the Ignition is switched off, which in turn shuts down the FI system.

Determining whether or not there is spark at the plugs (2a) —and whether or not the plugs are getting gas (3c)— will allow some analysis of this sequence.

For example, if 2a fails due to a bad Power Stage/Amplifier, there will be a no-start with gas-wet plugs. If 2b fails (practically never) symptoms will be Fuel-related: a no-start with spark at the plugs, but plugs remain dry.

--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Bruce, What does IAC stand for in step 3B? I went Over to Jon's to try and get him going. After we changed the cap and rotor the car did not start first try, on second try the car started but hard almost like it was either getting too much or to little fuel. When it finally wound up it ran very well, crisp throttle resonse and smooth idle. It was idling away smoothly while we where picking up thinking we had got it, it started skipping and then completly died out.

Ron Young
81 262C and others

Maybe the car builds up a little residual fuel pressure or something of that source while sitting there. Starts up but soon runs out fuel. Clogged something down the line.

IAC = Idle Air Control valve.

Sounds like you're back to square one again. I'd look at the plugs for spark while cranking, then wet or dry after no start.
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Swapped out ECU today with one from a 740 turbo. Same symptoms as before... what is left to check?

Fuel pump relay? Power stage? Have you checked for codes?

Fuel pump relay is good and no codes (that's a lie, there is one code 3-3-1, which I believe is speedometer related). Tonight I am attacking the power stage and the ICU. Any other suggestions?

http://www.brickboard.com/RWD/volvo/1311300/940/960/980/V90/S90/startup_sequence_wet_940.html

Everyone's going to love this one....I was out of gas. Well, not really. Disconnected the rail (should have done this after seeing if there was spark; see if there is fuel) and found that there was no fuel. Put in a couple gallons and car fired up once the rail got fuel. Diagnosis- intake fuel pump dead, leaving only main fuel pump to "suck" and hose from intank pump has split. Once the gas level is below the hose coming from the intank pump, the main pump would suck air, kind of like a straw with a hole in it in a glass of water. If the hole is below the water level, you can drink the water, but as soon as the hole is exposed you will suck air. Have yet to confirm this, but will keep posted once I tear into the fuel tank. However, this does not explain the fact that all three times the car died it was wet. Perhaps it was a coincedent or there were two problems and changing the cap solved the first.
Thanks to all who commented.

hello
i guess thats why you need fuel, spark, compression for starters.
its said the main pump wont last long without the intank.
94-95 940 went to one intank pump.
good luck